Son Goku

Son Goku is the most powerful fighter in the group; he can easily fight off any opposing demon with his nyoi-bou, a staff like weapon that can extend to any length or break apart into nun chuck like sections. Goku is a demon, and in order to remain in human form he wears a power limiter in the shape of a coronet. When this is removed, he goes berserk and is as likely to attack his allies as well as his enemies.

Goku was born from the earth and taken to heaven as something of a spectacle. However, something went wrong in heaven, and he was banished to earth and imprisoned beneath a mountain for five hundred years until Genjo Sanzo rescued him. Goku was unable to eat during his time under the mountain, and seems to be making up for it by consuming large amounts of food at every chance he gets.

Sun Wukong

Like Goku, Sun Wukong is also the most powerful member of the group. He has a verity of powers, including the ability to pluck a single hair from his head and transform it into a monkey horde. Unlike Goku, Sun Wukong is very intelligent, but he prefers to use his cunning for pranks and misuses his power to turn into 108 forms for this purpose.
           
Sun Wukong’s past is very similar to Goku’s—he was also born from the earth and taken to heaven, before being banished to earth again for his trickery. A goddess released him after five hundred years so he could accompany Xuanzang on his quest and act as a bodyguard to atone for his past sins. Sun Wukong also wears a coronet; the only difference is that Xuanzang can tighten it by murmuring a spell. The tightening gives Sun Wukong such a bad headache that he immediately stops misbehaving.

Comparison

Goku’s key features seem to be his dedication to Sanzo and his voracious appetite. Sun Wukong has neither of these attributes although they still seem quite similar. They each fight with the nyoi-bou, and are very powerful. Their pasts are almost identical, and although the circumstances under which they met their monk companions are slightly different, they both serve as their respective monk’s closest cohort and bodyguard.